Method for manufacturing a trim element

ABSTRACT

A cost-effective and resource-saving method for manufacturing a trim element, in particular a trim element which is used as a vehicle interior lining element. The trim element has a rear side reinforcement layer and a decorative surface. In the method according to the invention, a first layer is bonded in a first lamination step under pressure and heat to a first lamination and a second layer is bonded in a second lamination step under pressure and heat to a second lamination. The heat introduced in the second lamination step also acts in the first lamination and increases its bonding strength to the first layer.

FIELD OF THE INVENTION

The present invention relates to a method for manufacturing a trimelement, in particular a trim element which is used as a vehicleinterior lining element. Such interior lining elements can be liningelements for the center console or the doors or trim elements in thedashboard of the vehicle.

BACKGROUND OF THE INVENTION

Trim elements for automotive interior are nowadays produced, inparticular, in that a decorative layer which completely or partiallyforms the face side surface of the trim element is back injection moldedwith a reinforcement layer and provided on the face side with atransparent coating. Such a method is known from DE 41 24 297 A1. Withregard to good mechanical coupling of the rear side injection mold tothe decorative layer, it is also known to provide this decorative layerwith a lamination. The lamination is typically applied to the decorativelayer before the decorative layer is injection mold coated.

A method for producing a trim element is known from DE 10 2008 009 766A1, in which an upper and a lower nonwoven lamination are laminated ontoa material layer. In a first joining step, a precious wood veneer isbonded on the upper side of the material layer to the lamination. Thiscreates a multi-layer structure consisting of the wood veneer, the upperlamination layer and the material layer. The material forming the upperlamination layer has a lower activation temperature than the laminationmaterial on the underside. When the multi-layer structure is created,only the lamination provided on the upper side is then activated, butnot the lamination disposed on the underside. However, the conditionsare set such that even the lamination provided on the upper side doesnot fully cure. The multi-layer structure is then placed in an injectionmold and back injection molded to form a reinforcement layer. Thetemperatures and pressures acting there are there considerably higherthan the conditions for activating the lamination provided on the upperside. The lamination on the underside is then fully activated and theupper lamination layer provided on the oppositely disposed side hasfully set, which allows the precious wood veneer to glide and therebyperform a slight relative motion relative to the material layer beforeand during the injection molding due to the incomplete setting and thusprevent damage to the precious wood veneer during the back injectionmolding.

Various laminations which can also be used for the application of thepresent invention are known. The lamination can be formed by combining anonwoven material with adhesive. The lamination can be, for example,nonwoven fabric having adhesive applied on both sides. Such laminationsare typically applied to the decorative layer by flatbed lamination. Thelamination is there applied on a flat table. The decorative layer isplaced onto the lamination. The lamination and the layer are bonded toeach other subject to the application of pressure and temperature by adie driven against the table. The film of adhesive can be formed on thebasis of phenol, melamine, acrylic, polyurethane or their combinations.Such laminations are known and common, in particular, in the furnitureindustry. The film of adhesive is crosslinked by applying pressure andtemperature. It bonds accordingly with the layer.

An alternative lamination is formed by a mono-ply or multi-ply plasticfilm. Such a plastic film is usually calendered on. A multi-ply film istypically employed when, firstly, the lamination is to be adapted forthe best possible adhesion to the layer and for the best possibleadhesion to a layer placed thereagainst, for example, the rear sidereinforcement layer. In this case, one ply has particularly goodadhesion properties to the first layer and the other ply particularlygood adhesion properties to the second layer. Here as well, thelamination takes place by applying pressure and heat. The heat causesthe plastic material of the film to at least flow, the film is possiblymelted, whereby the adhesion with the layer(s) is improved.

For reasons of design, there is sometimes a need to arrange differentlayers as separate plies one after the other. For example, it is knownfrom DE 10 2012 016 147 A1 to first bond a first layer provided withthrough-holes to a second layer. The intermediate product thus formed isplaced in an injection mold to inject a reinforcement layer onto therear side of the second layer.

SUMMARY OF THE INVENTION

The present invention is based on the problem of specifying acost-effective and resource-saving method for manufacturing a trimelement with multiple layers.

A method having the features of an embodiment is proposed for thisaccording to the invention. In this method, the first layer is bondedsubject to the application of pressure and heat to a first lamination ina first lamination step. A second layer is bonded under pressure andheat to a second lamination in a second, subsequent lamination step. Theheat introduced in the second lamination step also acts in the firstlamination. The effect of the heat introduced in the second laminationstep into the first lamination is such that improved adhesive bondingbetween the first lamination and the first layer is obtained.

The first lamination step for bonding the first lamination to the firstlayer is typically carried out in such a way that the composite thusproduced is still incomplete. Energy in the form of pressure ortemperature is introduced only insufficiently during the firstlamination step, whereby resources can be saved in this first laminationstep. In the case of a crosslinking bonding agent which is part of thefirst lamination, this bonding agent is only slightly crosslinked orpartially crosslinked in the first lamination step. The maximum degreeof crosslinking for an activatable lamination after the first laminationstep is usually less than 50 percent.

In the second lamination step, the composite force between the firstlayer and the first lamination is increased.

In the case of a crosslinking bonding agent being part of the firstlamination, further possibly complete crosslinking is obtained also inthe first lamination due to the heat introduced in the second laminationstep. In any case, the adhesion of the first lamination to the firstlayer after the second lamination step has a better quality than afterthe first lamination step. The same applies to a bonding agent formed asthermoplastic material which is bonded to the first layer. Due to theheat introduced, the second lamination step causes adhesion withimproved quality over the adhesion obtained after the first laminationstep here as well.

The method according to the invention can be carried out favorably interms of energy efficiency. It is not necessary that the adhesion of thelamination to the associated layer is already completed in therespective lamination step. A temporally preceding lamination step caninitially instead be used only to adhere or bond the laminationassociated with the layer to the latter. A complete composite that meetspractical requirements does not have to take place already in thetemporally preceding lamination step. The process energy introduced inthe subsequent lamination step(s) is instead used to improve theadhesion between a layer and a lamination which were initially bonded ina temporally preceding lamination step. The process energy is there notconfined to heat input. The pressing pressure applied for a subsequentlamination step in conjunction with a pressing time can instead be usedsynergistically in the same way.

According to the invention, substantially planar, multi-ply intermediateproducts are respectively produced in the first and second laminationsteps. The lamination is there typically carried out in a flatbedlamination system. After the first lamination step, a substantiallyplanar ply composite has been produced. The first layer of the plycomposite is typically visible on the face side of the trim element andcan be formed by a veneer. In the second lamination step, this plycomposite is bonded at its rear side facing away from the face side tothe second layer. The first lamination provided between the first layerand the second layer is typically used to bond the first and the secondlayer to one another. The result in a substantially planar intermediateproduct, referred to as a sandwich structure, which is provided with thesecond lamination on its rear side. In the second lamination step, thissecond lamination is bonded to the second layer.

A lamination in the sense of the present invention is thereby a singleor multi-layer adhesion-promoting-sheet, which in the lamination stepbonds at least on one side to the associated layer. In the secondlamination step, the first lamination bonds to one surface of the secondlayer, whereas the second lamination bonds to the opposite surface ofthe second layer. In the case of a multi-layer adhesion-promoting-sheetbetween the first and second layer, the surface of theadhesion-promoting-sheet associated with the first layer can either bechanged or remain unchanged in the second lamination step due toadhesion. The second lamination connected to the second layer in thesecond lamination step is usually exposed at the back of the secondlayer after the second lamination step. The sandwich structure isprepared for the injection of a plastic material forming thereinforcement layer.

Pressures of between 0.5 and 2 N/mm² act in the first or secondlamination step, respectively.

The sandwich structure thus produced is typically trimmed in anintermediate step, so that the outer contour substantially correspondsto the contour of the finished product. Certain regions of the first orsecond layer can protrude beyond the final contour of the trim elementand be used for positioning or holding during the subsequent backinjection molding. Prior to the back injection molding, the initiallyplanar sandwich structure is deformed such that the contour of thesandwich corresponds to the three-dimensional contour of the trimelement to be produced. Thereafter, the rear side reinforcement layer isformed by fused arrangement of a plastic material against a rear side ofthe second layer and bonded to the second lamination, namely by way ofinjection molding.

The method is preferably carried out in such a way that the heatintroduced in a second lamination step takes the first lamination to atemperature not less than the maximum temperature in the firstlamination during the first lamination step. This further developmentcan be guided by the contemplation, that until the complete laminationof all layers, the temporally preceding lamination can initially takeplace incompletely in the sense that a temporally subsequent laminationstep to form another lamination also improves the adhesion between thelamination bonded temporally earlier to the associated layer.

With regard to economic procedure management, the pressing time or thepressing pressure, respectively, should also be applied in the samemanner. For the temporally subsequent lamination step, the pressing timeshould be longer than the pressing time applied in the temporallypreceding lamination step. The pressing time is the time in which thelamination is abutted under pressure against the associated layer. Thefirst pressing time is accordingly that time during which the firstlayer is abutted under pressure against the first lamination. Duringthis time, the process heat typically also acts at the phase boundarybetween the first lamination and the first layer. The pressing pressureused during the first lamination step does not necessarily have to beless than the pressing pressure of the second lamination step. However,the pressing pressure should not drop in relation to the pressureapplied in a temporally preceding lamination step.

The present invention can also be employed for multi-ply laminations,the individual plies of which are bonded to each other in a temporallysubsequent manner and to different layers. The ply of the laminationassociated with a first layer can be regarded as being the firstlamination within the meaning of the present invention, whereas thesecond ply abutted flat against this first lamination can be regarded asbeing a second lamination within the meaning of the present invention.This second lamination is typically directly bonded to the second ply inthe second lamination step. The process energy used there also improvesthe adhesion between the first ply, i.e. the first lamination, and thefirst layer.

The advantages of the invention discussed below with regard tolaminations on different surfaces of a single layer also apply to thespecifics described above. Nevertheless, it is preferable in practice toprepare multi-ply laminations first separately to form the respectivelayers and to combine them with one of the layers as a multi-plylamination. In this case, the second layer is abutted against the firstlayer prior to the second lamination step with the interposition of thefirst lamination. On the side of the second layer opposite to the firstlayer, the second lamination is bonded to the second layer in the secondlamination step. The process energy acting there also acts upon thephase boundaries between the first layer, the first lamination, and thephase boundary between the first lamination and the surface of thesecond layer. Not only the second lamination is thus bonded in thesecond lamination step to the second layer. The adhesion between thefirst layer and the second layer is further also improved through themedium of the first lamination.

With regard to the gentlest processing, in particular of veneers as thelayer of the trim element, it is preferable in the context ofmanufacturing the trim element to adjust the maximum temperature in eachlamination to be higher than the maximum temperature of the laminationpreceding on the face side. This further development can be guided bythe contemplation that the layer at the front on the face side is formedby a veneer and that the lamination that is in the context ofmanufacturing the trim element bonded on the rear side to the decorativelayer is taken to a lower temperature than the laminations that are moreremote from the face side. The veneer can then be bonded more gently tothe laminate in the back of the veneer than the layer provided underadhesive bonding of this lamination to the lamination associatedtherewith which is regularly disposed opposite to the veneer. In thiscase, the veneer represents the first layer, whereas the layer bondedthereto under the medium of the first lamination constitutes the secondlayer within the meaning of the present invention.

The present invention can be guided by the idea that the maximumtemperatures in the respective lamination are to be controlled. Due tothermally conductive processes, this maximum temperature can actuallyonly be measured after the completion of a lamination step. The temporalperformance of the lamination step and the measurement of the maximumtemperature can therefore differ in time.

In view of the most resource-efficient production as possible, thecontact pressure at least does not decrease between successivelamination steps. It can remain constant. The method is insteadpreferably carried out in such a way that the pressing pressure appliedin a subsequent lamination step is higher than that in the immediatelypreceding lamination step. The pressing times are also adjusted in acorresponding manner. It is only after the last lamination step that anadhesion is obtained that fulfills the practical requirements betweenthe individual laminations and the layers associated with them. Thefirst lamination step serves only to adhere the first lamination to theassociated layer. The process energy expended in the subsequentlamination steps improves this adhesion there.

According to a preferred further development of the present invention,the first and/or the second layer form the decorative surface of thetrim element on the face side. This decorative surface on the face sidecan be provided with a transparent coating. Accordingly, the surface ofthe first and/or the second layer does not necessarily also have to formthe outer surface of the trim element. However, the aesthetic appearanceof the trim element is predominantly determined by the surface of thefirst and/or the second layer.

According to a preferred further development of the present invention,the rear side reinforcement layer is formed by fused arrangement ofplastic material against a rear side of the first and/or the secondlayer. If the first layer determines at least predominantly the faceside decorative surface of the trim element, the fused plastic materialis abutted on the rear side against the second layer. This can be doneby injection molding or foaming, commonly in an enclosed cavity. Thepressure acting there and the temperature improve the adhesion of theplastic material to the second layer which on the rear side is providedwith the second lamination, where the second lamination causes theadhesive bonding between the plastic material and the second layer.Alternatively, the reinforcement layer can also be formed by pressingand/or casting processes, for example, non-pressure casting processes.

According to a preferred further development of the present invention,the first layer is provided with at least one through-hole after theapplication of the first lamination. This through-hole passes throughthe first layer and the lamination. A cavity pressure acting during theformation of the reinforcement layer on the rear side of the secondlayers presses a region of the second layer, which is located on therear side of the first layer, into the at least one through-hole. A trimelement can thus be obtained in which surface portions of the first andthe second layer are arranged side by side on the face side andsubstantially at the same level, as described by DE 10 2012 016 147 A1from the present applicant.

The through-hole or the several through-holes, respectively, are therepreferably recessed in the sandwich structure. For example, the firstlayer and the first lamination provided thereon can be penetrated bylaser cutting, but the second layer is not trimmed. This can becontrolled by the wavelength or power of the laser, in particular whenthe first layer is made of veneer and the second layer is made of metalfilm, for example aluminum.

Also when performing the method according to the invention, thelamination in the respective lamination step can be applied by way offlatbed, calender, rollers, wheels or a combination of these measures.In the case of a lamination from a multi-ply film, the two plies shouldbe formed from at least two different polymers. The plies of theindividual multi-ply film should be between 10 and 150 microns,preferably between 40 and 60 microns. In the case of lamination from amulti-ply film, the at least two plies should be formed from at leasttwo different polymers.

In particular a layer with a thickness of 0.05 to 0.5, preferably 0.05to 0.15 mm, in particular 0.1 mm is considered to be a layer within themeaning of the present invention. The latter dimensions apply inparticular to a metal film forming the layer. In the case of a layerformed by wood veneer, it should have a thickness of between 0.1 and 0.5mm, preferably 0.22 and 0.28 mm, in particular 0.25 mm. In this case,the metal film is preferably bonded by medium of the first lamination tothe veneer layer, whereas the metal film itself is bonded on the rearside to a second lamination in order to be, for example, directly bondedby a thermoplastic plastic to the film by back injection molding. Whenmanufacturing this specific embodiment, the first lamination is firstbonded to the veneer layer in a first lamination step. In a secondlamination step, the film is bonded on the rear side to a secondlamination. In this case, the film is already abutted in the context ofthe second lamination step with interposition of the first laminationagainst the rear side of the first lamination, so that the processenergy applied in the second lamination step also reaches into the firstlamination and the sandwich structure is obtained.

According to a preferred development of the present invention, a two-plyfirst lamination is used in the first lamination step. The first layeris bonded to a first lamination ply of the first lamination that isabutted against the first layer. In a second lamination step, the secondlayer on its side facing the first layer is bonded to a first laminationply of the first lamination abutted against the second layer and on itsside facing away from the first layer to the second lamination. The twoplies of the first lamination are there adapted to the respectivelamination steps. In the first lamination step, the first lamination plyabutted against the first layer is preferably fused or activated,respectively. The fusing is done in particular with thermoplasticlamination material. Activation is done with cross-linking laminationmaterial. In the material of the first lamination step, however, thefirst lamination ply of the first lamination to be abutted against thesecond layer is not fused or activated, respectively. This is only donein the second lamination step. To improve the adhesion of the differentlayers to each other, it is preferable to form the first lamination plyabutted against the first layer from thermoplastic material and to formthe first lamination ply to be abutted against the second layer fromcrosslinking material. This material is preferably identical to thatmaterial which is laminated against the second layer on the side of thesecond layer facing away from the first layer. Here as well, thelamination can be double-layered in order, firstly, to bond to thesecond layer as well as possible in the second lamination step and,secondly, to obtain the best possible bonding of the plastic materialforming the reinforcement layer. This can also be achieved, for example,in that the second lamination layer is formed by nonwoven fabric soakedin the direction toward the second layer, but which is still fibrous onthe opposite side and not soaked by the lamination material, so that itcan be penetrated at least in part by the fused plastic material whichthen bonds basically in an integrally formed manner.

In principle, the layers of each lamination ply can each be formed fromthermoplastic material or each from crosslinking material. Differentlayers of a single lamination ply can also be formed from differentlamination materials imparting the adhesion, in particular, firstly,thermoplastic material and, secondly, crosslinking material. Bonding onoppositely disposed sides of a decorative layer of the trim element arepreferably the same materials of the lamination ply imparting theadhesion. The decorative layer is a face side layer according to theembodiments, i.e. a layer of the trim element that defines anddetermines the structural configuration and to which the lamination plyadheres.

BRIEF DESCRIPTION OF THE DRAWINGS

Further details and advantages of the present invention shall becomeapparent from the following description of embodiments in combinationwith the drawing, in which:

FIG. 1 shows a schematic sectional view of a structure of a firstembodiment of a trim element in an exploded representation;

FIG. 2 shows a schematic sectional view of a structure of a secondembodiment of a trim element in an exploded representation.

FIGS. 3a to 3d show schematic sectional views for process steps formanufacturing a third embodiment of a trim element according to thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows different plies of a schematically illustrated embodimentof a trim element, where a layer marked with reference numeral 2 forms aface side surface 2 a which can be provided with a transparent ply as acoating, not shown. Disposed opposite to the face side surface 2 a is afirst lamination 4 which is bonded in a first lamination step to a rearside surface 2 b of the first layer. Located in a top view onto thefirst layer behind the first lamination 4 is a second layer 6. Disposedin the visual direction therebehind is a second lamination 8. Referencenumeral 10 indicates a rear side reinforcement layer.

In the finished trim element, all plies illustrated in FIG. 1 are bondedto each other. In the manufacturing process, the first lamination 4 isfirst bonded in a first lamination step to the first layer 2.Thereafter, the second layer 6 is abutted together with the secondlamination 8 on the rear side against the first lamination 4. The secondlamination 8 is bonded in the second lamination step to the second layer6.

The first lamination 4 is bonded to the first layer 2 subject to theapplication of pressure and heat over a predetermined time, hereafterreferred to as the pressing time. The pressing pressure applied there isP1; the temperature acting there is T1; the pressing time is t1.

In the first lamination step, this process energy introduced over thepressing time t1 can be introduced, for example, by flatbed lamination.Once the first layer 2, which can be, for example, a veneer, has beenstabilized by the first lamination 4, the combination of the first layer2 and the first lamination 4 is treated. The veneer first layer 2 canthen be ground, cut and/or provided with through-holes 12 (see FIG. 3b). The first lamination 4 acts not only as a bonding agent, but also asa reinforcement layer which supports the relatively thin veneer firstlayer 2 and protects it against damage during the subsequent treatment.

After treating the first layer 2 together with the first lamination 4,the second layer 6 is abutted against the rear side of the firstlamination 4 and at the same time the second lamination 8 is abuttedagainst the rear side of the second layer 6. This second lamination 8serves as a bonding agent for the later injection of the rear sidereinforcement layer 10 which is presently formed from a thermoplasticmaterial and is formed by way of back injection molding of theintermediate product formed from the layers 2, 6 and the laminates 4, 8.

In the context of the second lamination step, this lamination 8 isbonded to the second layer 6 by a heated plate which is abutted againstthe rear side of the second lamination 8. The heat introduced therewithinto the intermediate product passes through the second lamination 8 andthe second layer 6 applying heat and pressure in the direction towardsthe first lamination 4 and the first layer 2. The heat causes a heatingeffect there as well. In the event that the lamination 4 or 8,respectively, is made of nonwoven fabric that is applied adhesive onboth sides, the adhesive of both the first lamination 4 as well as thesecond lamination 8 is crosslinked by this heat. Partial crosslinking ofthe first lamination 4 effected in the first lamination step for bondingto the first layer 2 is completed accordingly. The crosslinking alsocauses adhesion to the first lamination 4 and the second layer 6. Themethod can there be carried out in such a way that heat introduced intothe first layer 2 and the first lamination 4 in the context of the firstlamination step is still present as a temperature increase in these twoplies 2, 4, so that the process energy introduced in the firstlamination step has not been completely lost when further process energyis introduced into the ply structure in the second lamination step.

The temperature of the second lamination 8 is T2; the pressure for thesecond lamination step is P2; the pressing time for the secondlamination step is t2. It is true that T2≥1; t2≥t1; P2≥P1.

T1 there refers to the temperature of the first lamination 4 in thefirst lamination step and T2 to the temperature of the second lamination8 in the second lamination step. This second lamination step leads to atemperature increase in the region of the first lamination 4. Thetemperature of the first lamination 4 during the second lamination stepis T1.2. A temperature increase of the first lamination 4 arises in thecontext of the second lamination step. This increases the temperature ofthe first lamination 4 in the context of the second lamination step. Themaximum temperature T1.2 is typically above the maximum temperature T1,i.e. the temperature of the first lamination 4 in the first laminationstep. However, the method should be carried out in such a way that thetemperature T1.2 is at all times lower than the temperature T2, also inthe second lamination step. This can be achieved in that the surfacesupporting the first layer on the outer side during laminating has alower temperature than the surface acting against the second lamination8. The respective ply structure is typically heated to a respectiveuniform temperature in the individual steps. The first temperature isusually selected in such a way that the first lamination is at leastpinned to the first layer. In the subsequent second step, the firstlamination is finally crosslinked or almost finally crosslinked, if thissecond step is the last lamination step.

FIG. 2 shows a similar structure of a trim element. Same components aredesignated with the same reference numerals. The respective laminationsare formed by a two-ply structure. The first lamination 4 has a faceside ply 4 a and a rear side ply 4 b. The face side ply 4 a isconfigured or adapted to the first layer 2 in terms of a good adhesionproperties. The rear side ply 4 b exhibits adhesion properties adaptedto the second layer 6. The multi-ply first lamination 4 is a two-layerplastic film formed from two polymer plies.

The second lamination 8 is also structured in a corresponding manner.The face side ply 8 a exhibits adhesion properties adapted to the secondlayer 6. The rear side ply 8 b exhibits adhesion properties for the bestpossible adhesion to the reinforcement layer 10.

A combination of the first and the second lamination of a single-layer(cf. FIG. 1) and a multi-layer (cf. FIG. 2) lamination are also possibleand conceivable.

FIG. 3a shows in a cross-sectional view a first layer 2 which is formedin the present case as a decorative layer in the form of a veneer havinga thickness of between 0.1, preferably 0.5 and 0.9 mm.

The first layer 2 is bonded to a first lamination 4 which has beenlaminated to the rear side of the first layer 2 with the application ofheat and pressure to the extent that the lamination is at least pinnedto the decorative layer and thus positioned.

The previously discussed through-holes 12 are punched out of the plycomposite from the decorative layer 2 and the lamination 4.

The first decorative layer 2 can by itself or together with the firstlamination 4 be shaped by cutting and be ground and calibrated to saidthickness, possibly be shaped to size or provided with support holes,respectively, in order to position and hold the first decorative layer 2on pins of an injection molding tool. By applying pressure andtemperature, the first decorative layer 2 can be transformed into athree-dimensional preform, for example, to produce a slight contouringon the face side and/or a curved optionally circumferential edge in theouter zones of the decorative layer 2. Also this treatment can becarried out with the lamination 4 provided on the rear side of the layer2. The heat acting in this process can either bond the lamination 4 tothe rear side of the layer 2 for the first time or improve an alreadycreated provisional bonding between the lamination 4 and the layer 2 byincreasing the degree of crosslinking within the lamination 4.

The first decorative layer 2 can also be treated by spraying a stain orbe ball-peened/surface-treated.

The decorative layer 2 presently has several separate island-shapeddecorative elements, of which only one is shown and marked withreference numeral 2 a, and which are each provided independently andwithout bonding to each other, but each provided with the lamination 4The through-holes 12 penetrate both the layer 2 as well as thelamination 4.

The second layer 6, which can be, for example, a plastic or metal film,which in turn is provided with the second lamination 8, is abuttedagainst this ply composite 14 shown in FIG. 3 a.

The heat acting in this second lamination step and the pressure actingthere causes the second lamination 8 to be laminated against the rearside of the second layer 6, but also leads to further or completecross-linking of the first lamination 4 and therefore to the firstlamination 4 curing, firstly, against the rear side of the first layer 2and, secondly, against the face side surface of the second layer 6.

The sandwich structure identified by reference number 16 in FIG. 3b isobtained after lamination. The through-holes 12 are preferably formedthere by laser cutting prior to or after the deformation of the sandwichstructure to create a three-dimensional molded part.

Prepared in this manner, the further intermediate product 18 shown inFIG. 3c is inserted into a tool half of an injection mold tool andpositioned there. A face side surface of the first layer 2 there abutsagainst a surface of the injection mold tool defining the cavity, theface side surface of the second layer 6 is disposed with a spacing andparallel to this surface defining the cavity, whereas a rear side, whichis formed exclusively by the second lamination 8, is exposed in thismold cavity and defines it.

A plastic component is now injected into the mold cavity and forms thereinforcement layer 10 on the rear side of the second lamination 8. Byback injection molding the reinforcement layer 10, the latter is bondedto the rear side of the second lamination 8.

The intermediate product 18 shown in FIG. 3c is deformed due to theinjection pressure acting and the afterpressure when the plasticcomponent solidifies. The second layer 6 is there pressed into thethrough-holes 12, so that the face side surface of the second layer 6 isarranged flush to the face side surface of the first layer 2. In thismanner, the plastic material of the reinforcement layer 10 solidifies,so that the trim element 20 shown in FIG. 3d as the product is obtainedin a dimensionally stable manner.

A transparent or transparently colored coating can now be provided onthe face side of this trim element 20 for protecting the product fromenvironmental influences or scratches on the face side. This can bedone, for example, in a turning tool which relocates the product shownin FIG. 3d in order to apply a coating on the face side produced byspray coating, presently with a transparent thermoplastic material suchas PMMA.

The energy introduced in each injection molding cycle in the form ofpressure and heat can be taken into account when optimizing the processparameters in view of a process that is as resource-efficient aspossible. The method can be carried out in such a manner that alllaminations have the degree of cross-linking required for the finalproduct only after the last or the only injection mold coating. In thismanner, the preceding lamination steps can be carried out while savingenergy, but nevertheless produce a finished product which meets thedemanded requirements.

In the embodiment shown, the first lamination 4 is laminated at atemperature of between 100° C. and 140° C. with an exposure time ofapproximately 30 to 40 seconds. In the second lamination step, thebonding between the second layer 6 and the first layer 2 takes place attemperatures of between 160° C. and 190° C. with an exposure time ofapproximately 100 to 140 seconds. Under these conditions, the secondlamination 8 is also abutted on the rear side against the second layer6.

LIST OF REFERENCE NUMERALS

-   2 first layer-   2 a island-shaped trim element-   2 b rear side surface-   4 first lamination-   4 a face side ply of the first lamination-   4 b rear side ply of the first lamination-   6 second layer-   8 second lamination-   8 a face side ply of the second lamination-   8 b rear side ply of the second lamination-   10 reinforcement layer-   12 through-holes-   14 ply composite-   16 sandwich structure-   18 intermediate product-   20 trim element

What is claimed is:
 1. A method for manufacturing a trim element, inparticular a trim element for the automotive interior, with a rear sidereinforcement layer and a face side decorative surface; in which a firstlayer is bonded under pressure and heat in a first lamination step to afirst lamination for producing a substantially planar ply composite, inwhich a second layer is bonded under pressure and heat in a second,subsequent lamination step to a second lamination, where in the secondlamination step, said second layer is abutted against said firstlamination and heat introduced in said second lamination step also actsin said first lamination, so that said second layer is bonded to saidply composite via said first lamination to produce a substantiallyplanar sandwich structure, where said rear side reinforcement layer isformed by a fused arrangement of a plastic material against a rear sideof said second layer and bonded to said second lamination.
 2. The methodfor manufacturing a trim element according to claim 1, wherein the heatintroduced in said second laminating step takes said first lamination toa temperature not less than a maximum temperature in said firstlamination in said first lamination step.
 3. The method formanufacturing a trim element according to claim 1, wherein a pressingpressure introduced in said second lamination step is not less than apressing pressure in said first lamination step.
 4. The method formanufacturing a trim element according to claim 1, wherein a pressingtime of said second lamination step is not less than a pressing time ofsaid first lamination step.
 5. The method for manufacturing a trimelement according to claim 1, wherein said second layer is abuttedagainst said first layer with the interposition of said first laminationprior to said second lamination step.
 6. The method for manufacturing atrim element according to claim 1, wherein, in the context ofmanufacturing said trim element, a maximum temperature in eachlamination, or with a multi-ply lamination in each ply, is not higherthan a maximum temperature in the lamination or ply preceding on theface side.
 7. The method for manufacturing a trim element according toclaim 1, wherein, in the context of manufacturing the trim element, apressing pressure of a temporally subsequent lamination step is not lessthan a pressing force of a temporally immediately subsequent laminationstep subsequent to this lamination step.
 8. The method for manufacturinga trim element according to claim 1, wherein, in the context ofmanufacturing said trim element, a pressing time of a temporallypreceding lamination step is shorter than a pressing time of atemporally immediately subsequent lamination step preceding thislamination step.
 9. The method for manufacturing a trim elementaccording to claim 1, wherein said first and said second layer form theface side decorative surface of said trim element.
 10. The method formanufacturing a trim element according to claim 1, wherein said firstlayer after application of said first lamination is provided with atleast one through-hole penetrating said first layer and said firstlamination and that a cavity pressure acting when forming saidreinforcement layer on said rear side of said second layer presses aregion of said second layer, which is located on a rear side of saidfirst layer, into said through-hole.
 11. The method for manufacturing atrim element according to claim 10, wherein said through-hole isrecessed in said sandwich structure.
 12. The method for manufacturing atrim element according to claim 1, wherein a two-ply first lamination isused in the first lamination step, that said first layer is bonded to afirst lamination ply that is abutted against said first layer and that,in a second lamination step, said second layer on its side facing saidfirst layer is bonded to a second lamination ply abutted against saidsecond layer and on its side facing away from said first layer to saidsecond lamination.
 13. The method for manufacturing a trim elementaccording to claim 10, wherein a two-ply first lamination is used in thefirst lamination step, that said first layer is bonded to a firstlamination ply that is abutted against said first layer and that, insaid second lamination step, said second layer on its side facing saidfirst layer is bonded to a second lamination ply abutted against saidsecond layer and on its side facing away from said first layer to saidsecond lamination.
 14. The method for manufacturing a trim elementaccording to claim 12, wherein said first lamination ply that in thefirst lamination step is abutted against the first layer is fused oractivated, but not said second lamination ply of said two-ply firstlamination.
 15. The method for manufacturing a trim element according toclaim 1, wherein the heat introduced in said second laminating steptakes said first lamination to a temperature not less than the maximumtemperature in said first lamination in said first lamination step andthat the pressing pressure introduced in said second lamination step isnot less than the pressing pressure in said first lamination step. 16.The method for manufacturing a trim element according to claim 1,wherein the heat introduced in said second laminating step takes saidfirst lamination to a temperature not less than a maximum temperature insaid first lamination in said first lamination step and that a pressingtime of said second lamination step is not less than a pressing time ofsaid first lamination step.
 17. The method for manufacturing a trimelement according to claim 1, wherein the pressing pressure introducedin said second lamination step is not less than the pressing pressure insaid first lamination step and that a pressing time of said secondlamination step is not less than a pressing time of said firstlamination step.
 18. The method for manufacturing a trim elementaccording to claim 1, wherein the heat introduced in said secondlaminating step takes said first lamination to a temperature not lessthan a maximum temperature in said first lamination in said firstlamination step, that the pressing pressure introduced in said secondlamination step is not less than the pressing pressure in said firstlamination step and that the pressing time of said second laminationstep is not less than the pressing time of said first lamination step.19. The method for manufacturing a trim element according to claim 1,wherein said second layer is abutted against said first layer with theinterposition of said first lamination prior to said second laminationstep and that, in the context of manufacturing said trim element, amaximum temperature in each lamination, or with a multi-ply laminationin each ply, is not higher than the maximum temperature in thelamination or ply preceding on the face side.
 20. The method formanufacturing a trim element according to claim 1, wherein said secondlayer is abutted against said first layer with the interposition of saidfirst lamination prior to said second lamination step and that, in thecontext of manufacturing the trim element, the pressing pressure of atemporally subsequent lamination step is not less than the pressingforce of a temporally immediately subsequent lamination step subsequentto this lamination step.
 21. The method for manufacturing a trim elementaccording to claim 1, wherein, in the context of manufacturing said trimelement, a maximum temperature in each lamination, or with a multi-plylamination in each ply, is not higher than a maximum temperature in thelamination or ply preceding on the face side and the pressing pressureof a temporally subsequent lamination step is not less than the pressingforce of a temporally immediately subsequent lamination step subsequentto this lamination step.
 22. The method for manufacturing a trim elementaccording to claim 1, wherein said second layer is abutted against saidfirst layer with the interposition of said first lamination prior tosaid second lamination step and that, in the context of manufacturingthe trim element, a maximum temperature in each lamination, or with amulti-ply lamination in each ply, is not higher than a maximumtemperature in the lamination or ply preceding on the face side and thepressing pressure of a temporally subsequent lamination step is not lessthan the pressing force of a temporally immediately subsequentlamination step subsequent to this lamination step.
 23. A method formanufacturing a trim element, in particular a trim element for theautomotive interior, with a rear side reinforcement layer and a faceside decorative surface; in which a first layer is bonded under pressureand heat in a first lamination step to a first lamination, in which asecond layer is bonded under pressure and heat in a second, subsequentlamination step to a second lamination, wherein the heat introduced insaid second lamination step also acts in said first lamination.
 24. Amethod for manufacturing a trim element with a decorative layercomprising the steps of: bonding a first layer to a first laminationpartially with a first pressure and a first temperature forming a firstply composite; placing a second layer adjacent the first lamination ofthe first ply composite; and bonding a second lamination to the secondlayer with a second pressure and a second temperature sufficient tocreate additional bonding between the first layer and the firstlamination, whereby bonding between the first layer and the firstlamination is increased during the step of bonding the second laminationto the second layer.